Carbon-based nanomaterials (e.g. carbon nanotubes, graphene fullerenes) have unique electronic, optical, and physical characteristics which make them useful in a variety of applications. Driven by these potential industrial scale applications, these nanomaterials are increasingly being produced in very large/bulk quantities. Most applications require a large degree of control to be demonstrated over the characteristics of these materials. However, many of the manufacturing processes yield heterogeneous products. For example, most single-walled carbon nanotubes (SWNT) synthesis techniques produce mixtures of semiconducting and metallic SWNT. Semiconducting SWNT are desirable for use in field effect transistors and energy harvesting, whereas metallic SWNT hold a great deal of potential for application as transparent electrodes and antennas. Each application requires highly pure semiconducting or metallic SWNT samples. Furthermore, many of the applications for which such SWNT are highly desirable involve chemistry or processing in which purification or selectivity for the desired products remains an inhibitory issue, particularly at large scales.
Accordingly, improved compositions, methods and systems are needed for separating carbon-based nanostructures.